Couples who inject a little variety into their sex lives over the years are just as sexually satisfied as they were during the first six months of their relationship, according to the one of the largest studies ever to examine what contributes to a satisfying sex life long-term.

"Just about everyone agrees that sexual satisfaction is an important component in long-term relationships," lead author David Frederick, assistant professor in health psychology at Chapman University, told me Tuesday. "Who we choose to be our partner, how we get along with our partner and our sex life with that partner are such a central part of our lives."

The study looked at 38,747 married or co-habitating heterosexual couples who had been together three or more years. The men and women ranged in age from 18 to 65, and many had been together for two decades or more. (Frederick said a similar study on same-sex couples is in the works.)

"If properly nurtured, passion can last for decades," the study states. "Nearly two-thirds of sexually satisfied respondents reported that their sex lives now were as passionate as in their early days together. Over one-third of sexually satisfied men and women selected 'passionate' as the single best word (out of six) to describe their most recent sexual encounter."

And check this out: Kids don't necessarily wreck your sex life.

"How many kids were living in the house wasn't really related to sexual satisfaction at all," Frederick said. "Just having kids in the house didn't seem to matter as much as other things like mood setting, frequency of sex, consistency of orgasms, how well a couple communicates."

The biggest predictor of long-term satisfaction is willingness to try new things. Close to half of all couples — satisfied and dissatisfied — read sexual self-help books and magazine articles, according to the study. "But what set sexually satisfied couples apart was that they actually tried some of the ideas," Frederick said.

"If you have sex three times a week with your partner, that's more than 150 times per year," he said. (An optimist, this guy.) "Over 10 years you've had sex with your partner 1,500 times. There's a lot of potential for it to become habitual or routine. But trying novel things can really help in the sexual realm."

It's not so different in the bedroom. (Or those other rooms. Novelty!)

In general, the results indicate that couples who prioritize each other's satisfaction and can confide in each other with new ideas — without fear of judgment or rejection — fare the best.

Satisfied men and women were more likely than dissatisfied men and women to say they did one of the following: tried a new sexual position, wore sexy lingerie, took a shower or bath together, talked about or acted out fantasies, gave or had a massage, went on a romantic getaway or used a sex toy together.

Couples who stayed satisfied long-term also reported more frequently setting a romantic mood by lighting candles or playing music, and were more likely to communicate about their feelings for each other, such as saying "I love you" during sex or sending flirty texts during the day.

They also found that sexually satisfied men and women gave and received more oral sex, had more consistent orgasms and engaged in more frequent sex.

Isn't that last one a bit of a chicken/egg thing, I asked Frederick?

"There is definitely a bi-directional relationship," he said. "Generally it spirals: If you say your sex life is predictable, that makes you less satisfied and that makes you avoid sex. Your attitude about sex can fuel both satisfaction and dissatisfaction."

As with most things in life, it all comes down to your attitude. (And your willingness to try some kinky stuff.)

The study, co-authored by Janet Lever of California State University, Los Angeles, Brian Gillespie of Sonoma State University and Justin Garcia of the Kinsey Institute at Indiana University, will appear in The Journal of Sex Research next week.

A version of this article appeared in print on February 14, 2016, in the Life+Style section of the Chicago Tribune with the headline "Variety maintains satisfying sex life" —
Today's paperToday's paper | Subscribe